Sperm Competition

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School

University of Toronto Scarborough

Department

Anthropology

Course

ANTC23H3

Professor

Joyce Parga

Semester

Summer

Description

Sperm Competition Male Reproductive AnatomySocial Stimulation and Human Sperm CountJuly0312Sperm count higher from ejaculations 105 PMSperm competition Terms resulting from sexual intercourse than from Raffle Principle Sperm Competitionmasturbation A males likelihood of When sperm from two or more The less time a couple has spent together fertilization success males compete to fertilize the since their last intercourse the higher the depends on the number of same eggssperm count in the males ejaculation sperm sperm he produces and Occurs whenever a female mates competition inseminates with more than one male during Sperm precedence her fertile period Male fertilization success Relative testes size in males depends on mating order indicates level of sperm Last male sperm competition precedence the last Size in relation to the body male to mate with a size of the animal female is most likely Larger relative size more to inseminate the sperm competition because female more sperm is produced First male sperm Apesprecedence first Common chimps and bonobos male to mate with a have the largest relative testes female is most likely size highest sperm competition to inseminate the Fits with mating system female polygynandrous Not 100 assured Orangutans Sperm precedence in Smaller relative testes size primates than chimps larger than Mouse lemur gorillas Found that earlier Copulatory PlugsAgain fits with dispersed mating males had Also called sperm plugs basically when ejaculate mating system higher success not coagulates inside the female Gorillas necessarily the first Secretions of the prostate gland are needed for Little to no sperm mating male coagulation to occur compeition Optimal insemination Copulatory plugs conform to vaginal wallPolygyny period is during early Not all primates have them Gibbons and siamangs receptivityIn humans semen further liquefies within 20 Little to no sperm Some researchers argue minutes of ejaculation competition that sperm precedence Can form within seconds but may or may not be visible Monogamy doesnt truly exist for any following ejaculation Specific to RTL Mating Systems and Sperm mammals Can remain intact for at least 12 days dont liquefyCompetitionSay its by chance HypothesisHighest to lowest because there are a Barrier hypo